Improvement in domes



UNITED STATES ILLAM RUMBOLD. 0F S'l. LUIS, MISSOURI.

IMPRQVEMENT lN DOMES.

Spccilicntion forming part oi'Letters Patent No. 35,630, dated June 17,19419.

To all whom it may concern:

Be it known that I, WILLTAMRUMBOLD, of St. Louis, in the State ofMissouri, have invented a new and useful Improvement in the Constructionof Metal Denies; and I do hereby declare that the following is a full,clear, and exact description of the same, reference being had to theaccompanying drawings, forming part of this specilication, in which-Figure 1 is avcrtical section of the frame or skeleton of a domeconstructed according to my invention. Fig. 2 is an enlarged perspectiveView of the same. Fig. 3 is a horizontal or cross section of the same.Fig. 4 is a. View similar to Fig. 2, but showing a. solid beam. Fig. 5is a horizontal or cross section of Fig. 4.

Large metal domes have com monly been constructed of sectional beams andwith an auxiliary supporting-conc or framelwork, and in no instance havesuch domes been sustained simply by the thrust braces or beams and thebands tying them together-that is, no practical demonstration of a domethus sustained has ever been made in this or any other conn try prior tothe demonstration thereof by myselfon the courthouse in the city ei' St.Louis, State of Missouri, within the past two years.

The principle of construction adopted by me whereby this importantresult is accomplished consists in providing for the confining of thethrust upon arched ribs of domes by the construction of the arched ribsin one unbroken length and with inner and outer shoulder projections,and placing strong wrought-iron bands upon the entrados and intrados ofthe arched ribs, the whole being done in such manner that the skeletondome becomes, as it were, one solid mass and constitutes a rigidstructure possessing great strength in proper tion to its weight, andwhile the bands confine the thrust ol' the arch beams or ribs, the ribsin turn support the bands and prevent them moving either upward ordownward, and thus insurge their acting to prevent or conline thethrust,and also prevent buckling or spreading and twisting of the ribs.

To enable others skilled in the art to make and use my invention, I willproceed to describe it with reference to the drawings.

B B are arched ribs of wronght-ironor other suitable .metal, and withbroad inner and outer edges and a narrow solid wel. They also areconstructed with notched brad projections E E on their inner and outerarched edges. These ribs are made in one solid length, and not of piecesspliced together so as to form breakjoints, as proposed in some works onthe construction of wooden domes. The solid construction of the beamsgives great strength and lightweight. The ribs, of course, must taperfrom bottoni to top gradually, se as to conform to the intended contourof the dome. In width inward or outward they may be uniform from top tobottom. The ribs thus constructed are secured by their lower ends andshoes D placed thereon tothe wallplnte A of the rotunda oi' a building1as shown in Figs. 2 and 4, and supported at their upper ends by meansol' a ring, C.

Between the shoulders formed by the notched projections E E strongwrought-iron hands G and li arc placed, so as to encircle the wholeseries of ribs internally as well as ex ternally, so to speak, or, inother words, hind them internally and externally. The hands G, which areplaced on the entrados of the ribs, resist the tendency of the ribs tothrust outward. These bands, being supported by the shoulders of theprojection E, cannot he come displaced by any amount of strain which cancome upon them, and therefore they resist to the full extent ol' theirtensile strength any force tending to crush the dome.

To further strengthen the dome hy preveniing buckling or twisting of theribs under crushing strains, bands H are placed upon the -intrados ofthc ribs, securing them between `the shoulders oi' projection E' in thesame manner as the bands G, or dispensing with the shoulders at thispoint, as circumstances muy demand, and depending upon strong bolts. Theshoulders however, answer better 'than anything else for very heavydomes. Thus a rigid framework is formed and the metal therein sodisposed that but little lateral strain comes upon any part, and whilethe thrust is verticahor in the line of the arch, it is confined andborne by the bands to the extent of their tensile capacit-y.

By these means I am enabled to construct a dome which is very muchlighter in proportion to its span 4than any heretofore made, and Withoutany aid from auxiliary internal supporting-cones or frame-work, as hasbeen demonstrated in a dome of sixty feet diameter built according to myinvention.

I would here state that a beam or rib with trellis-work wrought upon itmight be employed by taking two narrow arch-ribs made iu one solidlength and connecting them together by diagonal pieces, as illustratedin Figs. 2 and 3. In this constructionthe bands G and H would beappliedand would act just the same as in the construction shown in Figs. l, 4,and 5.

I am not aware that solid arch-beams constructed as described and bandedclosely from shoulders, as shown.

Having now fully set forth my invention, what I claim as new therein,and desire to secure by Letters Patent, is-

A metal dome constructed substantially as herein described, for thepurpose set forth.

WILLIAM RUMBOLD.

Witnesses:

R. W. FENWICK, DE WITT C. LAWRENCE.

